1665390564 has 48 divisors (see below), whose sum is σ = 4323639040. Its totient is φ = 554364000.

The previous prime is 1665390563. The next prime is 1665390599. The reversal of 1665390564 is 4650935661.

1665390564 is a `hidden beast` number, since 1 + 66 + 539 + 0 + 56 + 4 = 666.

It is not an unprimeable number, because it can be changed into a prime (1665390563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70842 + ... + 91374.

Almost surely, 2^1665390564 is an apocalyptic number.

It is an amenable number.

1665390564 is an abundant number, since it is smaller than the sum of its proper divisors (2658248476).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1665390564 is a wasteful number, since it uses less digits than its factorization.

1665390564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21297 (or 21289 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 45.

The square root of 1665390564 is about 40809.1970516451. The cubic root of 1665390564 is about 1185.3284268327.

The spelling of 1665390564 in words is "one billion, six hundred sixty-five million, three hundred ninety thousand, five hundred sixty-four".